The inner tube on my bike burst the other day, I took it home and salvaged another one from a bike that's been sitting unused in my garage for years.

The New(old) innertube inflates fine but when I inflated it I noticed that the inner tube was spilling out through a gash in the stitching of the tire.

I've temporarily replaced the tire with another that I had lying about but the ripped one was a semi slick and the one I've replaced it with is a mountain biking one, I'd prefer a semi slick tire.

I know I'm going to have to replace the tire as well.

The new inner tube seems spongier and I can't seem to get it to inflate as much as the old one.

I'm a relatively new to (serious) cycling, and this is the first time I've had to replace an inner tube or a wheel.

I mainly cycle on roads and cycle paths, the cycle path I use it just rough enough for me not to justify getting a full on road bike.

Question

What do I need to know in order to go into a shop and get the right replacement inner tube/ tire for my bike? I'm aware that there are different sizes of tyre (mine is 26") and there is another number which I assume is width (Old was 1.5"). Is this all I need to know?

Do I need to know anything about the inner tubes? I assume the size is the same as the tire, are there different grades or types of inner tube? Why would one be spongier than the other?

2 Answers
2

I think I understand the issue. Just to clarify, is this what happened:

Burst tyre. Replaced tube with one left lying around.
This revealed a split in the sidewall, thus the tyre is now gash.
Now looking for a new tyre to replace the old one.

All mountain bikes (well, almost all. But we'll leave that aside for the moment) have 26" diameter wheels, so that shouldn't be a problem.

Mountain bike tyres tend to come in toroidal diameters of 1.9-2.35". They also tend to be fairly flexible to help with grip & dampening down impacts. This will be why you're feeling the difference between them.

Commuting/slick tyres seem to com in 1.25-1.5". They will have a harder casing, be more resilient and (obviously) lack all the knobbles.

Ok, answer time:

You need a 26" tyre. I'd go for something that matches your remaining functional tyre, so you want a 1.5". Be aware that not all companies' tyres come up the same (Specialized come up big for the measurement & Panaracer come up small).

after that there are some choices to be made. If you can afford it, you want to replace with a "folding" tyre. This means that the bead around the edge of the tyre is made of kevlar or similar plastic rather than steel wire. This makes the tyre lighter (and thus easier to accelerate or brake) and, crucially makes it easier to get on and off in the case of another puncture.

Different tyres offer different levels of protection against punctures & pinch flats. It's best to have a look at each individually.

Oh, Daniel makes a good point about valves. The chances are you're on Schrader (car type), but look at what's on the other wheel.

Regarding tubes themselves. They're pretty much much of a muchness. Specialized ones are good, continental ones are fine but pricey. Only buy something that has a brand on the box.

Regarding tubes, again Daniel is spot on. They come with a range of sizes. So long as your tyre is within that range you'll be fine (though Mel's been running 1.5-2.2 tubes in a piar of 2.35 tyres for about 6 months without any issues).

I strongly advise NOT getting a folding tire. They are much harder to mount, especially if you're a novice.
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Daniel R HicksOct 12 '11 at 12:23

Every tyre has a number on the side, e.g. 559-45 for a 45mm MTB tyre. These ETRTO codes can be used to make sure you are getting a compatible tyre.
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ʍǝɥʇɐɯOct 12 '11 at 13:01

@DanielRHicks: do you mean they're harder to mount because they're loose and don't stay in place? (I had that problem in a hot day, 2.4 soft tyre)
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bigstonesOct 12 '11 at 16:11

1

They arrive flat. They do not have a "tire shape". You have to somehow get them onto the rim and somehow get the tube inside to inflate the first time so they will take a "tire shape". After that they're not as bad. Probably it's not so much of a problem for someone with some experience with them, but they really have no real advantages over steel-beaded tires, other than a miniscule amount of weight, so why bother?
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Daniel R HicksOct 12 '11 at 18:15

Basically you just need a tube that's the right size (diameter and width) for the tire. And of course you need the right stem -- the thin Presta stem, or the thick auto-style Schraeder stem -- depending on what your rim is drilled for.

There are various grades of tubes, but you most certainly want just the standard grade. Thin ones designed for racing leak down rapidly, while thick ones designed to resist punctures are really bulky and hard to deal with.

Be wary of a shop that doesn't have the right size tube (the range of sizes should be printed on the box the tube comes in) and tries to sell you what they have in stock. While a "slightly wrong" size will often work, it will be hard to install and will be apt to not run smoothly.

[Also note that for a small cut in a tire you can often get away with using a "boot" behind the hole. This can be a specially made piece of thin, flexible plastic, a piece cut from the sidewall of a lightweight tire, or even a piece of folded currency, if yours (as in the US) is fairly rugged.]